Why Track Axial Length, Not Just Prescription: A Practical Guide to Myopia Progression Tracking

The myopia epidemic is a data problem too

Hong Kong has some of the highest childhood myopia rates in the world. According to the Department of Health's Student Health Service myopia page, about 18% of 6-year-old students are already short-sighted, rising to about 62% by age 12. And the trend is worsening: a CUHK population-based study found that myopia prevalence among 6-year-olds doubled from 12.7% in 2015 to 25.0% in 2021 following COVID-19 restrictions, and remained at record-high levels even after restrictions were lifted. The issue has reached policy level: in April 2026 the government set out its measures to protect students' visual health in the Legislative Council.

Clinically, the response is well established: regular follow-up, and interventions such as low-dose atropine, orthokeratology, and myopia-control spectacle lenses. But there is a quieter problem underneath the clinical one — most of the data that myopia management depends on still lives on paper printouts. Autorefractor slips, biometry reports, and visual acuity records pile up in folders, and the longitudinal picture that actually drives decisions has to be reconstructed by hand at every visit.

This guide covers what modern myopia management tracks, why axial length deserves a central place in your records, and how to digitize the workflow without adding staff.

Why prescription alone isn't enough

Most clinics summarize a child's myopia with spherical equivalent (SE) — sphere plus half the cylinder. SE is essential, and its trajectory across visits is the number parents ask about. But SE has limitations as a progression metric:

• It is an optical measure, influenced by accommodation and measurement conditions (cycloplegic vs. non-cycloplegic refraction can differ meaningfully in children).
• It changes in relatively coarse steps, so slow progression can hide inside measurement noise between two visits.
• It does not directly measure the anatomical change that creates long-term risk.

That anatomical change is axial elongation — the eye physically growing longer. Excessive axial length is what drives the sight-threatening complications of high myopia later in life, including myopic maculopathy and retinal detachment. The International Myopia Institute's Clinical Management Guidelines, published in the peer-reviewed journal IOVS, treat axial length as a core measurement in myopia management and give concrete reference points: elongation of roughly 0.1 mm/year is associated with normal eye growth, while 0.2–0.3 mm/year is associated with progressing myopia. Optical biometry makes the measurement objective and repeatable to a fraction of a millimeter — it tracks the structural change itself, not just its optical consequence.

The practical takeaway: track SE and axial length together. SE tells you what the child sees; axial length tells you how the eye is growing and whether an intervention is actually slowing that growth.

What a good myopia record looks like

For each patient, a useful longitudinal record includes:

1. Spherical equivalent (right and left eye) at every visit, noting whether refraction was cycloplegic
2. Axial length (right and left eye) from optical biometry — the IMI guidelines recommend measuring every 6 months, shortening to 3 months for fast progressors
3. Visual acuity (uncorrected and corrected)
4. Current intervention — atropine concentration, ortho-k, myopia-control lenses, or none — with start and change dates
5. Visit dates, so progression can be expressed as change per year, not just change between visits

The last point matters more than it looks. A −0.50 D change means something very different over 4 months than over 14 months. Annualized progression rates — for both SE and axial length — are what let you compare a patient against the IMI's reference ranges and against their own history, and they are the fairest way to judge whether an intervention is working.

The workflow gap: from printouts to trends

Here is what the workflow looks like in many clinics today:

1. The autorefractor and biometer each print a slip.
2. The slip is stapled into a paper file, or its values are retyped into a spreadsheet.
3. At the next visit, someone flips back through the file to answer: how fast is this child progressing, and did the intervention change that?

Every step is manual, and retyping introduces transcription errors exactly where precision matters most — when the clinically meaningful signal is 0.1 mm of axial change per year, a misplaced digit is the difference between "stable" and "progressing." Spreadsheets help, but they still depend on someone entering data consistently and building charts by hand, and they rarely survive staff turnover.

Digitizing the workflow with OCR

This is the gap that BioTrack was built for. Instead of retyping printouts:

1. Photograph or scan the printout — the autorefractor slip or biometry report, as-is.
2. AI-powered OCR extracts the structured values — SE, axial length, and other refraction and biometry fields — in seconds, with a review step so you confirm every value before it is saved.
3. The trend builds itself. Each patient gets longitudinal charts of SE and axial length across visits, with deltas and regression trends computed automatically, and interventions recorded alongside so you can compare progression before and after starting treatment.

The clinical judgment stays with you; the software removes the retyping, the filing, and the chart-building. A free plan (25 patients, 50 OCR scans per month) makes it practical to trial the workflow on your myopia-management cohort before committing.

Frequently asked questions

How often should axial length be measured in myopia management? The IMI Clinical Management Guidelines recommend every 6 months where a biometer is available, shortening the interval to around 3 months if a patient appears to be progressing quickly.

Can axial length be tracked without an optical biometer? Optical biometry is the practical standard for precise, repeatable axial length measurement in clinic. If your practice doesn't have a biometer, SE progression remains valuable — but consider referral pathways for baseline biometry in fast-progressing children.

Does BioTrack work with my device's printouts? BioTrack's OCR is designed for photographed or scanned examination printouts and includes a review-and-edit step before saving, so extracted values are always confirmed by a human. You can try it free with your own printouts.

The bottom line

Myopia management is a longitudinal discipline: the value is not in any single measurement but in the trend. Track spherical equivalent and axial length, annualize the rates, record interventions with dates — and stop reconstructing that picture from paper at every visit. The clinics that digitize this workflow answer the only question parents ask — "is it slowing down?" — with a chart instead of a guess.

BioTrack by Vibing Company turns medical exam printouts into structured patient data and longitudinal myopia trends. Learn more about BioTrack or start free.